Ok guys I’ve still got the vibration which feels like it’s in the front end.
The suspension has been completely change with the exception of the lower control arms. Brand new P-4000 tires balanced on a Hunter 9700 and they all balanced well within spec. And the drive shaft has been balanced with new U-joints in the drive shaft and half shaves.
Now for the crazy info. The vibration is not near as bad with the new tires compared to the old Michelins. The vibrations seems to be worse the longer I drive and on warmer days. For example, I won’t feel the vibration as much in the morning when it’s cool but in the after noon, after sitting out all day on the black top, it’s much worse. This leads me to believe its temperature sensitive. So what in the suspension is temperature sensitive and will cause a vibration? This is driving (no pun intended) crazy!
Thanks
Mike

 

Fan clutch / WP bearing?? Try disconnecting your fan belt for a minute and see if it goes away.
Brian

 

Harmonic balancer?

 

When it's vibrating, shift into neutral and coast. Does it go away? Shut off engine/coast, vibe gone? Running with clutch in/out, what then? All these type of things will help you narrow it down.

 

Sorry about that!
The vibration happens somewhere around 65 to 75 mph and it varies.
To answer the rest of the questions shifting to neutral or holding in the clutch doesn’t change anything but please keep trying! If it was the harmonic balancer wouldn’t I feel it all the time?
I was thinking the rag joint or the steering box but in all my years I’ve never messed with either so I have very little experience. I also have power steering…could something there be temperature sensitive?
Thanks
Mike

 

Carefully check your front wheel bearings and rotor run out.

 

The Hunter 9700 both balances and checks for radial force variation and wheel runnout, however, unless you ask for a check of radial force variation and wheel runnout, it will probably not be done, and tire shops will typically charge extra for these additional services.

The point here is that just because the tires are balanced on a 9700 doesn't mean that the radial force variation and tire and wheel runnout are acceptable unless you request that these analyses by done. So if you had these additional tasks done, what are the numbers?

It would help if you would describe the vibration in more detail - vehicle speed or RPM sensitive? What speed or RPM? Where do you feel/see the vibration? Bodywork? Steering wheel?

Duke

 

The radial force was completed and I believe the numbers were all in spec. As I recall 12 or 13 are the magic numbers and my range was around 8 to 10.
The vibration varies as to speed. Sometimes I start feeling it 65 mph but never any higher than 75. I feel most of it in the steering wheel, a little at my feet (sometimes) and you can always see it in the hood shake. I really didn’t pay attention to the RPM’s as it relates to the vibration but I think we’re about 2500.
The thing that is really puzzling is it doesn’t happen all the time. My drive to work is about 40 minutes and is 85% freeway. By the time I hit the freeway the car is warmed up and I take it right to 70 mph. No vibration at this point and the care is running real smooth. Just about 30 minutes into the mission I start feeling some vibration but minimal. Now the car has sat out in the sun all day on the black top, I head home and no sooner than I hit the freeway I start feeling the vibration. It may hit around 65 so I speed up to about 72 and it goes away. I travel at 72 for a short and it starts to vibrate and it’s like that all the way home. If you haven’t been to Columbus, Ohio it’s fairly flat so the speed verses work load doesn’t change much. On the way home I tried the holding the clutch in and it’ didn’t make any difference.
This really sucks!
Thanks
Mike

 

Sounds to me like a detoriated rubber buffer that heatens up and looses its stiffness....have you checked differential mount and tranny mount as well as the motor mounts ?

 

Rubber mounts?
That’s one place I haven’t tried. Going a step further what about the body mounts? Could that also be a problem?
I’ve replaced many motor mounts but never tranny or differential rubber while they were still attached to the drive line. Is this doable without total dismantle?
Thanks for the ideas!

 

The Hunter 9700 operator should have measured the wheel runout. Do you know what the readings were?

You mentioned that you had the same problem with the previous set of tires. How long have you owned the car? Did you ever NOT have the vibration problem?

Is the hood vibration that you are seeing up and down or right to left? Is the vibration bad enough so that you can obviously tell if one side is worse than the other?

I had a (sort of) similar problem with a car that I have and I KNOW that it had a (steel) wheel with a radial runout of about 0.04". I can put on a set aluminum wheels and the problem vanishes.

What air pressure are you running in the tires? In my case lowering the tire pressure helped somewhat. I normally run about 32 lbs. in my tires (cold) but on a hot day at freeway speeds the air pressure would climb to over 45 lbs. My theory was the "hardness" caused by the pressure rise in the tires exacerbated the out of round condition.

Charles

 

That was my thought in mentioning the vibration damper. In addition to it and other rubber pieces, heat could also change tire stiffness/compliability and exacerbate a radial runout/out of round problem.

 

WOW!
I really appreciate the interest and suggestion.
1. I’m not sure of the runout of the wheels.

2. The wheels are AR’s TT II customs with about 5,000 miles on them now. I purchased them new.

3. The problem started when I had a blow out. The tires were Goodyear’s and the were about 5 years old. At the time of the blow out (nail in the side wall) the tires were out of production so I replaced all 4. I went with Michelins 225-60-15. The vibration started! I went for an alignment and found the trailing arms were shot and from there I’ve replaced just about every suspension part trying to solve the vibration problem. My last resort was the tires. I just put on P-4000 and am running at about 32 lbs. cold.

4. The hood vibration seems to be right to left.

The rubber mount idea really sounds good cause of the randomness of the vibration. I would think if runout was the problem it would be constant.
Thanks again guys, I really appreciate the help

 

I assume you have tried swapping the wheels/tires front to rear and this does not alter the vibration?

Charles

 

Check the runout!!!

 

Charles
"I assume you have tried swapping the wheels/tires front to rear and this does not alter the vibration?"
Yes I did and no it didn’t!
Ron
I will check the runout but wouldn’t the vibration be more consistent if the runout was the problem?

 

blue66,

My brother is in the tire business in Dallas and suggests the following:

1. Lost wheel weight thrown off tire due to improper installation. (This happened to me once within 3 blocks of the tire dealer).
2. Loose lug nuts or incorrect nuts that don't have the same taper at the wheel lug nut openings. This can cause the wheel to be loose.
3. Wheel (not tire) runout. He said a lot of wheels are not truly round when manufactured and sometimes slip past QC. He said American Racing wheels have had problems in the past.
4. If you swap wheels and tires front to back same side, and the condition still exists in the steering wheel, then its suspension or tie rod related. If you feel it in your butt, then it's most likely an out of balance or out of round tire/wheel combo.

My thoughts......I had a tie rod problem once on a Mustang that drove me nuts. Also, check your wheel bearings. Jack up each side of your car and support it, then grab the tire horizontally and check for play. Do the same vertically. Have someone watch your outer tie rod ends for movement. Good luck.

 

You may wan to swap wheels from another car and see what happens. If the vibration is still there, then you will know if the tires are not the cause.

 

What's the front wheel bearing clearance?

Also, are the wheels hub centric or bolt-centric. Jack the front end up, spin the tire and eyeball across the crown looking for runnout. Could be a wheel mounting eccentricity problem.

Also, a badly out of balance drum or disk could be a cause. If you can find a place that has an old on-the-car spin balancer, it might be worth having it checked. If it's significantly out of balance with a known good wheel/tire balance the drum or rotor is the first suspect.

If the front bodywork shakes the problem is likely in the front end rotating parts or front suspension/steering joints.


Duke

 

Hi Blue

I have a couple of questions - my car picked up a vibration after swapping the differential that puked on the Hot Rod Power Tour for one of my spare diffs. I believe I know where the source of my problem is, and it may be yours too.

What wheel took the blowout that started the problem? Did you mount the spare and drive home? If not - what did you do? If so, and if it was a rear wheel, how far did you drive?